The present invention is directed to a ladder, and more particularly, is directed to a bunk ladder for installation in an over-the-highway tractor.
A ladder is a well known apparatus for providing an access path to an elevated area. Conventional ladder designs include two parallel elongated rails connected by a series of equally spaced rungs. Fixed ladder designs of this type are impractical in confined areas that prohibit transporting and maneuvering of the ladder into and out of useable positions.
One example of a confined area requiring a ladder is the sleeping berth of an over-the-highway tractor. Over-the-highway tractors often contain a sleeping berth in which a driver may rest during periods of non-driving. When an operator is required to travel for an extended period of days, often a second operator or a companion passenger, accompanies the driver because of safety concerns. To accommodate two persons, some over-the-highway tractors contain a sleeping berth with twin bunk beds. In these tractor designs, a ladder is required for ingress and egress to the upper bunk.
A conventional sleeping berth containing bunk beds presents several challenges to the design of a suitable ladder. The relatively tight configuration of the sleeping berth allows little room for maneuvering a ladder in and out of a useful position. Further, a suitable ladder must be securely fastened to the bunk when in use for operator safety. However, when not in use, any ladder installed in the berth must be unobtrusive to the driver and passenger of the tractor.
Typical bunk beds installed in tractors are asymmetric in size. The top bunk of many tractor designs is hinged in several places against the back berth wall. Consequently, the upper bunk can be rotated up to be stowed flush with the back wall when not is use. Therefore, any ladder design that mounts on the top bunk must allow for storage of the upper bunk. In addition, the width of the top bunk is often less than the width of the bottom bunk, further challenging ladder design.
A need exists in the market for a ladder design that is easy to operate, is self storing in an unobtrusive position when not in use, and accommodates asymmetric application environments.
The adjustable grab handle of the present invention provides a ladder apparatus for installation in a variety of application settings. The ladder includes a telescoping feature and adjusts to a range of application lengths, while allowing storage in a relatively small area when not in use. The invention is beneficial to original equipment manufacturers, such as over-the-highway tractor manufacturers.
In a first embodiment, a ladder apparatus for installation in an environment to aid access to an elevated area within the environment is disclosed. The apparatus includes an upper member and a lower member.
The upper member includes an elongated first side rail, an elongated second side rail and at least one step rung. The elongated first side rail includes a mounting end, an open end, and a center portion extending between the mounting end and the open end. At least the part of the center portion disposed adjacent the open end is hollow. The mounting end has structure for rotateably mounting the first side rail to a first mating surface. The open end defines an aperture.
The elongated second side rail includes a first end, a second end, and a center portion extending between the first end and the second end. The first end has structure for rotateably mounting the second rail to a second mating surface. The at least one step rung is rigidly disposed between the first and second side rails.
The lower member includes a first end, a second end, and a center portion extending between the first end and second end. The lower member first end is slideably engaged within the upper member open end to define a ladder length. The second end has structure for removably mounting the lower member to a third mating surface when the ladder is in use and to a fourth mating surface when the ladder is in storage.
A length of the ladder is adjustable over a range by sliding the lower member with respect to the upper member.
The lower member second end may include a latch mechanism. The latch is adapted to alternatively be removably fixed to the third mating surface or to the fourth mating surface.
The second side rail may include a portion essentially parallel to the at least one step rung such that the portion forms a second step rung. The second side rail second end may terminate at the first side rail. The upper member and the lower member may be constructed of extruded plastic.
The apparatus may include a spring disposed within the elongated first side rail. The spring is connected between the first side rail mounting end and the lower member first end. The spring will extend when the apparatus is in use and recoil when the apparatus is in storage.
In a second embodiment, in an over-the-highway tractor having a sleeping berth containing a bunk system, the system including a back wall, an upper bunk frame, a lower bunk frame, and a ladder for aiding operator access to the upper bunk, an improved ladder is disclosed.
The ladder includes an upper member and a lower member. The upper member includes an elongated first side rail, an elongated second side rail and at least one step rung. The elongated first side rail includes a mounting end, an open end, and a center portion. At least the part of the center portion disposed adjacent the open end is hollow. The mounting end has structure for rotateably mounting the first side rail to a first mating surface defined by the upper bunk frame. The open end defines an aperture.
The elongated second side rail includes a first end, a second end, and a center portion. The first end has structure for rotateably mounting the second rail to a second mating surface defined by the upper bunk frame. The at least one step rung is rigidly disposed between the first and second side rails.
The lower member includes a first end, a second end, and a center portion. The lower member first end is slideably engaged within the upper member open end to define a ladder length. The second end has structure for removably mounting the lower member to a third mating surface when the ladder is in use and to a fourth mating surface when the ladder is in storage.
The third mating surface is defined by the lower bunk frame and the fourth mating surface is defined by the upper bunk frame. A length of the ladder is adjustable over a range by sliding the lower member with respect to the upper member. The range is at least from a storage length to an application length.
The application length may be essentially equal to the distance from an outermost point of the upper bunk frame to an outermost point of the lower bunk frame. The storage length may not exceed a length of the upper bunk frame. The ladder nests when mounted in a stored position adjacent an underside of the upper bunk frame.
The apparatus may include a spring disposed within the elongated first side rail. The spring is connected between the first side rail mounting end and the lower member first end. The spring will extend when the apparatus is in an application configuration and recoil when the apparatus is collapsed to a storage configuration.
Further advantages and a fuller understanding of the invention will be had from the accompanying drawings and the detailed description of the invention.